No filmmaker has done more than Jia Zhang-ke to show the harsh reality of 21st Century China to the rest of the world. His latest revisits and refines what he has done before: tales of vast social upheavals and lives being booted around to suit the latest state whim; lots of images of small individuals pictured against vast industrial developments.

Ash also encompasses his own development from making semi-documentary pictures to more conventional narratives and it builds specifically on two of his previous films, one from either end of that journey. From 2006's Still Life, it takes footage of the Three Gorges before the completion of the dam, plus a random interest in UFOs. It is also another go at what he attempted but couldn't quite pull off with his previous film Mountains Might Depart: telling a melodramatic tale over a long time period that reflects the story of his country.

Starting in 2001 in the Shanxi province, we meet gangster Brother Bin (Fan Liao) and his lady Quio (Tao Zhao.) He seems pretty amiable by gangster standards. There's a scene where he and Quio are dancing energetically to YMCA by Village People and his gun drops out on to the disco floor. But the local mine is threatened by closure and a new breed of young thugs are making their presence felt. Upheaval is coming and the story follows the pair's fates up to the present day. Or 2017, the present day when it was filmed.

There is nothing here that Jia Zhang-ke hasn't attempted before but the slow burn soap opera and the use of pop songs to express deeper emotions is gently devastating. The story is rooted in a great sacrifice that isn't rewarded or recognized, and of course that has a meaning beyond the lives of these two characters but it is all so gently presented, so subtle, it would feel heavy handed to bang on about it being an allegory. Fortunes are fickle for his two protagonists but there has been a steady through line for Jia Zhang-ke: these are ideas he's been working on and building up to for over two decades and Ash is their purest expressions.